Sorting PHP Array by ISO Date - php

Question

I am trying to sort an array in PHP by date and time which is in ISO 8601 format. I am still trying to grasp PHP and have tried many of the solutions on stack overflow and I am just not able to nail down the right function. Hopefully this is an easy answer and it will be helpful to others.
FYI, this array was generated by the Citrix API for GoToMeeting. I would like to sort the array based on startTime in the soonest time first in the list.
Here is what the array looks like using var_export with two results presented:
array (
0 => stdClass::__set_state(
array(
'createTime' => '2012-07-03T19:36:58.+0000',
'status' => 'INACTIVE',
'subject' => 'Client 1',
'startTime' => '2012-07-10T14:00:00.+0000',
'conferenceCallInfo' => 'United States: xxxxx Access Code: xxxxx',
'passwordRequired' => 'false',
'meetingType' => 'Scheduled',
'maxParticipants' => 26,
'endTime' => '2012-07-10T15:00:00.+0000',
'uniqueMeetingId' => 12345678,
'meetingid' => 123456789,
)
),
1 => stdClass::__set_state(
array(
'createTime' => '2012-07-02T21:57:48.+0000',
'status' => 'INACTIVE',
'subject' => 'Client 2',
'startTime' => '2012-07-06T19:00:00.+0000',
'conferenceCallInfo' => 'United States: xxxxx Access Code: xxxxx',
'passwordRequired' => 'false',
'meetingType' => 'Scheduled',
'maxParticipants' => 26,
'endTime' => '2012-07-06T20:00:00.+0000',
'uniqueMeetingId' => 12345678,
'meetingid' => 123456789,
)
),
)
My goal is to then output the array into html div's using a foreach loop, this code is complete and works well but my sort is off :-)
Thank you in advance for any help!
Steve

Answer 1

You can implement any sorting technique you can think of if you wrap it in a callback and use usort() docs here
inside your callback, you can use strtotime or similar, and do simple int comparisons.
$myDateSort = function($obj1, $obj2) {
$date1 = strtotime($obj1->startTime);
$date2 = strtotime($obj2->startTime);
return $date1 - $date2; // if date1 is earlier, this will be negative
}
usort($myArray, $myDateSort);